When using airsoft guns, the size and shape of the face of each player is not the same, and consequently, the airsoft guns may not contact the face properly to well support the face. In addition, since each player has different gripping methods and habits, a buttstock has to be adjusted to a suitable length so that the buttstock may contact against the chest of the player when the airsoft gun is changed to a rifle. There are conventional length adjustable buttstock structures in the market. The conventional length adjustable buttstock structure is operated by two elements: a handle and a fastening structure. When to extend the buttstock, first the fastening structure is released to separate the buttstock structure from a barrel (which typically called “Buffer Tube”), then the handle is pressed to make the buttstock away from a gear portion in the barrel, and thereby extension or shorten of the buttstock is completed (the foregoing descriptions relate to the known length adjustable buttstock structures in the market). Although the length of the buttstock can be adjusted using the aforesaid structure, the structure is complicate and has too many components, thereby resulting in high assembling and production costs and other problems.
In view of the foregoing, the inventor made various studies to improve the above-mentioned problems by providing a simple structure to adjust the buttstock or a cheek piece, so as to enhance the practical utility in the industries.